So, I'm using ASUS X550Z laptop with FX-7500 Radeon R7 APU (512MB VRAM) and R5 M230 dedicated GPU (2048MB VRAM) in Dual Graphics configurations. Problem is that I can't use R5 card ONLY, I have to use it as duet of R7+R5, or R7 only. I don't want to use it in Crossfire, because then I'll be using only 512MB of both cards, which will result in only 1024MB VRAM, when I want to use full 2048MB. Here are tests I tried to do in GTA V:
[All in PowerPlay on Maximum Performance, and with laptop power settings set as Maximum Performance, laptop plugged in; in GTA settings: lowest settings, DX10]
1 - Crossfire OFF, Dual Graphics OFF - 18-30 FPS, avg. 24FPS, game uses 512MB of VRAM
2 - Crossfire ON, Dual Graphics ON - 24-35 FPS, avg. 28FPS, game uses 1024MB of VRAM
3 - Crossfire OFF, Dual Graphics ON - 25-39 FPS, avg. 29FPS, game uses 1024MB of VRAM
And here lies the problem. In ANY configuration I can't use full 2048MB of my R5 card. Tests done in Guild Wars 2, CS:GO, World of Tanks, osu!, and Civilization VI are nearly same. In any of this games I can't use full of my VRAM. Yes, I've tried Overdrive, it doesn't change a thing.
AMD Quad Core FX-7500 APU with Radeon R7
Radeon R5 M230
500GB HDD + external 1TB HDD
Dual Monitor configuration (through D-SUB DE-15F output) with Eyefinity disabled
Windows 10 (up to date)
Drivers version: 17.10.1731-170424a2 (updated like 2 days ago).
@EDIT: One game, that uses full of VRAM is... GTA: San Andreas. Because I can choose which card I want to use.